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通过控制温度与p H,研究胃蛋白酶在不同处理条件下对大豆分离蛋白水解模式的影响及产物乳化性和起泡性的影响。结果表明:p H2.0,37℃时,选择性水解11S组分;p H3.8,70℃时,选择性水解7S组分;p H2.0,70℃时,11S组分与7S组分均被水解;p H3.8,37℃时,11S组分与7S组分几乎不发生水解。水解产物乳化特性显示11S被选择性水解后,乳化活性与乳化稳定性均显著提高,分别从0.724,25 min提高到1.716,38.2 min;7S被选择性水解的蛋白乳化活性没有改善,但乳化稳定性提高到29.6 min;而11S与7S均被水解后,蛋白乳化活性提高到1.417,乳化稳定性则较差。各水解产物的起泡能力与泡沫稳定性均显著提高,其中水解产物在p H4.5处上清的起泡能力最强,接近未水解蛋白的4倍,7S被水解的蛋白在p H4.5处上清的泡沫稳定性最好,约为未水解蛋白的1.2倍。
The effects of pepsin on the hydrolytic mode of soy protein isolate and the emulsifiability and foaming of the product under different treatment conditions were investigated by controlling temperature and p H. The results showed that: p H2.0, selective hydrolysis of 11S components at 37 ℃, p H 3, selective hydrolysis of 7S components at 70 ℃, p H2.0, Points are hydrolyzed; p H3.8,37 ° C, 11S components and 7S components almost no hydrolysis. The emulsification properties of hydrolyzate showed that the 11S was selectively hydrolyzed, the emulsifying activity and emulsifying stability increased significantly from 0.724,25 min to 1.716,38.2 min, respectively. The emulsifying activity of 7S hydrolyzed protein did not improve, but the emulsifying stability The sexuality increased to 29.6 min. However, after both 11S and 7S were hydrolyzed, the emulsifying activity increased to 1.417 and the emulsifying stability was poor. The foaming ability and foam stability of each hydrolyzate were significantly improved. The hydrolyzate had the highest foaming capacity at p H4.5, nearly 4 times of the unhydrolyzed protein, and the 7S hydrolyzed protein was at p H4. The stability of the foam of the 5 supernatants was best, about 1.2 times that of the unhydrolyzed protein.